1. Field of Invention
The invention relates generally to the field of providing content to one or more users over a distribution network. In one exemplary aspect, the invention relates to methods and apparatus for reducing switching delays in a network providing IP packetized content to users.
2. Description of Related Technology
The provision of content to a plurality of subscribers in a content distribution network is well known in the prior art. In a typical configuration, the content is distributed to the subscribers devices over any number of different topologies including for example: (i) Hybrid Fiber Coaxial (HFC) network, which may include e.g., dense wave division multiplexed (DWDM) optical portions, coaxial cable portions, and other types of bearer media; (ii) satellite network (e.g., from an orbital entity to a user's STB via a satellite dish); (iii) optical fiber distribution networks such as e.g., “Fiber to the X” or FTTx (which may include for example FTTH, FTTC, FTTN, and FTTB variants thereof); (iv) Hybrid Fiber/copper or “HFCu” networks (e.g., a fiber-optic distribution network, with node or last-mile delivery being over installed POTS/PSTN phone wiring or CAT-5 cabling); (v) microwave/millimeter wave systems; etc.
Various types of content delivery services are utilized in providing content to subscribers. For example, certain content may be provided according to a broadcast schedule (aka “linear” content). Content may also be provided on-demand (such as via video on-demand or VOD, free video on-demand, near video on-demand, etc.). Content may also be provided to users from a recording device located at a user premises (such as via a DVR) or elsewhere (such as via a personal video recorder or network personal video recorder disposed at a network location) or via a “startover” paradigm, which also affords the user increased control over the playback of the content (“non-linear”).
Just as different varieties of content delivery services have evolved over time, several different network architectures have also evolved for deploying these services. These architectures range from fully centralized (e.g., using one or more centralized servers to provide content to all consumers) to fully distributed (e.g., multiple copies of content distributed on servers very close to the customer premises, at the “edge” of the distribution network), as well as various other configurations. Some distribution architectures (e.g., HFC cable, HFCu, etc.) consist of optical fiber towards the “core” of the network, which is in data communication with a different medium (coaxial cable radio frequency, copper POTS/PSTN wiring) distribution networks towards the edge.
Satellite networks similarly use a radio frequency physical layer (i.e., satellite transceiver and associated settop box and satellite dish located at each of the consumer's premises) to transmit digital television and data signals.
“WiMAX” technology, specified in inter alia IEEE-Std. 802.16e, offers high data rate, wireless access and content delivery to network subscribers at literally any location, fixed or mobile. This technology ostensibly provides MSOs and other service providers a flexible and high-bandwidth means of delivering content to their subscribers, and is especially well suited to both fixed and mobility applications due to its comparatively long range (much greater than WLAN technologies such as Wi-Fi), and wireless (air) interface.
Other systems and methods may also be used for delivering media content to a plurality of subscribers. For example, so-called “Internet Protocol Television” or “IPTV” is a system through which services are delivered to subscribers using the architecture and networking methods of an Internet Protocol Suite over a packet-switched network infrastructure (such as e.g., the Internet and broadband Internet access networks), instead of being delivered through traditional radio frequency broadcast, satellite signal, or cable television (CATV) formats. These services may include, for example, Live TV, Video On-Demand (VOD), and Interactive TV (iTV). IPTV delivers services (including video, audio, text, graphics, data, and control signals) across an access agnostic, packet switched network that employs the IP protocol. IPTV is managed in a way so as to provide the required level of quality of service (QoS), quality of experience (QoE), security, interactivity, and reliability via intelligent terminals such as PCs, STBs, handhelds, TV, and other terminals. IPTV service is usually delivered over a complex and heavy “walled garden” network, which is carefully engineered to ensure sufficient bandwidth for delivery of vast amounts of multicast video traffic.
IPTV uses standard networking protocols for the delivery of content. This is accomplished by using consumer devices having broadband Internet connections for video streaming. Home networks based on standards such as “next generation” home network technology can be used to deliver IPTV content to subscriber devices in a home.
So-called “Internet TV”, on the other hand, generally refers to transport streams sent over IP networks (normally the Internet) from outside the network (e.g., cable, HFCu, satellite, etc.) that connects to the user's premises. An Internet TV provider has no control over the final delivery, and so broadcasts on a “best effort” basis, notably without QoS requirements.
There is also a growing effort to standardize the use of the 3GPP IP Multimedia System (IMS) as an architecture for supporting IPTV services in carriers networks, in order to provide both voice and IPTV services over the same core infrastructure. IMS-based IPTV may be adapted to be compliant with the IPTV solutions specifications issued by many IPTV standards development organizations (SDOs), such as, e.g., Open IPTV Forum, ETSI-TISPAN, ITU-T, etc.
Extant Internet TV and IPTV solutions (regardless of bearer medium) lack several fundamental capabilities now being demanded by users, including a desire for a user experience which mimics that of traditional broadcast systems in terms of providing swift and smooth channel changing or so-called “channel surfing” capabilities in a bandwidth and network efficient way.
One improved architecture and associated methods for packetized (e.g., IP) content delivery are described co-owned, U.S. application Ser. No. 12/841,906 filed on Jul. 22, 2010 and entitled “APPARATUS AND METHODS FOR PACKETIZED CONTENT DELIVERY OVER A BANDWIDTH-EFFICIENT NETWORK”, now U.S. Pat. No. 8,997,136 issued on on Mar. 31, 2015, which is incorporated herein by reference in its entirety. This architecture addresses the foregoing shortcomings of IPTV and Internet TV. However, the aforementioned smooth channel surfing capabilities are still desirable in such an architecture. Prior art methods for handling channel changes involving packetized content focus generally on providing a low resolution version of a requested program up to a point in time where the buffer of the viewer's set-top box is sufficiently filled. Then, the set-top box or the video server initiates a switch to the multicasted high resolution version of the channel. The low-resolution version ostensibly has the advantage of buffering faster, and hence reducing delay or latency to some degree. While these methods take into account viewers' tendency to traverse through the channels that lie between their current channel and their desired channel if the “distance” is short, they do not take into account other alternative tendencies of the viewer (for example, the viewers' tendency to jump to a distant channel).
In order to provide the ability to reduce delay in the prior art methods, certain channels may be selected for caching and therefore are pre-buffered and ready for immediate viewing. However, the prior art fails to provide a system which is able to determine when to provide cached background channels and when to cease the delivery and/or caching thereof.
Accordingly, what are needed are improved methods and apparatus to reduce latency in channel switching in a network, especially for networks carrying multiple channels of Internet protocol (IP) content. Such apparatus and methods would ideally provide efficient latency reduction during instances of channel surfing, and would predict times or instances where the user is likely to begin channel surfing.